Transcript for Trump expected to deliver tough talk to North Korea in UN address

Jon Karl, thanks very much. We bring in chief global affairs correspondent Martha Raddatz to talk more about this. Okay, so the president's speech today, expecting tough talk when it comes to North Korea. Those are words, what about actions, Martha? Well, as Jon said, robin, he will call on the world to help but a military option does remain on the table. Defense secretary Jim Mattis emphasized that again on Monday. But he added something very intriguing to his comments saying there are military options that would not put south Korea's capital Seoul at grave risk if the U.S. Acted against North Korea. When you have Seoul with 10 million people just 35 miles from the north Korean border and you know that Kim Jong-un would retaliate, that is one reason a military option is so ugly but Mattis would not go into detail but experts say it could be a cyberattack or something they believe Kim would not respond to or could not respond to militarily, robin. What about the recent military exercises? Do they at least send some sort of message to North Korea? Robin, these most recent exercises are live fire exercises. They are real bombs on the warplanes and I went up in an f-16 fighter jet to the border which the U.S. Patrols constantly. They were not armed. This week's exercises do send a strong message but Kim knows what the U.S. Is capable of doing and knows very well it is an option that no one wants to use and he surely factors that in, as well. Which is why he continues with his nuclear program, robin. That's it. All right, Martha, thank you

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North Korea launched another missile over Japan, prompting several to call for an emergency U.N. meeting. This is at least the fifth time North Korea has sent a missile over Japan. ABC's Joohee Cho reports.

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